The potential of insect frass for sustainable biogas and biomethane production: A review

Insect-based protein production has gained traction in recent years. This has led to the increasing production of frass, the residual substrate from insect farming. As a relatively new substrate with characteristics that are not widely known, its energetic potential still needs to be investigated. In this context, this literature review aims to evaluate the potential of frass as a feedstock for bioenergy production through anaerobic digestion. From the literature search, 11 studies were selected, and showed a wide range of biogas (44 m3/ton VS to 668 m3/ton VS) and methane (26 m3/ton VS to 502 m3/ton VS) production potentials from insect frass, mostly comparable with traditional biomasses of liquid and solid slurry. Results are influenced by factors such as substrate type, digestion conditions and presence of co-digestion substrates. The need of further investigation on the economic viability has been highlighted, with a focus on the possibility of upgrading biogas to vehicle-grade biomethane.